Thanks to Peder for getting the earlier message out. Hopefully the advance
notice of our message tonight will allow some of you the opportunity to try
and look for this bird. The best time is not until midday as you will be
looking generally east and the sun will be a problem early in the day. You
will need a scope.
We are well aware how hard it is to differentiate subadult Franklin's and
Laughing gulls. In fact it may not be possible without a better (and closer
look) than we had today. Nevertheless, we believe that this is probably a
Laughing Gull because of several factors. All these points refer to a
standing and preening gull. We were never able to see it in flight. The
dark gray back clearly points to one of these two species. Black-headed
Gull, while having a darker head, is eliminated because of its' lighter back
color.
Some of the coverts and tertials appeard to have substantial remnants of
juvenile or first winter plumage. This generally brown plumage is present
in this area in a first winter Franklin's Gull or a first summer Laughing
Gull according to Olson and Larsson (Gulls of North America, Europe, and
Asia.) This is August so a first winter plumage would have to be really
severely retarded by nearly six months or so and we don't believe that this
is realistic. We should add that when we first saw this bird we suspected
Laughing Gull because we have never seen a Franklin's that looked like this
anywhere near this time of year. It just didn't look right for a Franklin's
at all.
The tips of the tertials appeared to display no white edging. Franklin's
Gulls tend to show some very minimal white as early as first winter and in
first summer they show extensive white edging to the tertials. Laughing
Gulls tend to not show white edging to the tertials until the second winter
phase. In first summer and first winter white edging is very minimal. Even
accounting for the distance that we were viewing this bird, we believe that
we would have been able to see white edging if it was more than very
minimal. By the way we were viewing this bird with the bright sun behind us
(occasionally behind light clouds) and with enough of a breeze that we
experienced no heat waves through our 50 power scopes.
The folded wing tips did not show any white spotting. Franklin's Gulls
shows white spotting (from the wing tips) as early as first summer while
Laughing Gull does not show much white spotting till the adult plumage. One
of us got a good long look at the top of a raised wing (while the bird was
preening) and no white was evident between the black tips and the dark gray
top area of the wing. David Sibley in his guide (the only one we had with
us at the time) shows some white in this raised wing area as early as first
summer for Franklin's and basically never in Laughing Gull.
From looking at the Sibley Guide today, and Olson and Larsson tonight, it
appears that the bottom of the wing is somewhat diagnostic in
differentiating these two species. As I said we were unable to see this
bird in flight. One of us got a short look at the bottom of one wing while
it was preeening and felt that the wing showed a lot of darkness as compared
to what you would see in a Franklin's Gull. Franklin's tend to be very
white in the underwing area except for the black tip while Laughing tends to
show more extensive dark areas. Clearly we probably did not get a good
enough look at this underwing area.
Laughing Gull has a longer bill than a Franklin's Gull. We were not able to
tell anything with the distant study we had of this bird. With no
comparison the length seemed to be of no help to us in figuring this out.
The bird did not have the typical dark head of these species in adult
plumage but it did show extensive shading of black throughout the head.
Generally summer subadult Franklin's have their black primarily on the back
half of the head. Laughing tends to have black in more extensive areas of
the head although not the deep black of adults. We definitely felt this
favored Laughing Gull.
Similar to this is the fact that Franklin's Gull from first winter on shows
a very clean white neck, chest, and side of chest while Laughing Gull shows
some smudging in these areas. Depending on which book you look at you get a
different idea of how much smudging is on the Laughing Gull but both books
show this very clearly until they reach adult plumage. The bird today had
smudging on the neck and the sides of the chest. It didn't appear to have
much in the center of the chest but it was very clearly on the sides and
neck.
We should add that we looked at this bird for well over and hour and a half,
during which time the bird did little except walk around along the edge of
one of the islands that the gulls were on. When we looked away for a short
time one of the numerous eagles or the locally persistent Peregrine Falcon
flew low over the gulls and they shuffled their position. We were unable to
refind the gull after that point. We do not believe that it left the area.
It probably just shuffled to the back of the flock or the back of the island
and we were blocked from seeing it. In future days it may take more than
one stop at this place to find it.
Something to consider is what species is more likely in this area at this
time of year. We believe that the closest nesting area for Franklin's Gull
would be Agassiz NWR although nonbreeding birds are seen further south off
and on in western MN. We haven't looked this up but suspect based on our
experience that nearly all of these sightings of these nonbreeding birds are
in the northwestern quarter of MN this time of year. Laughing Gulls are
regularly reported in Missouri and we think occasionally in southern Iowa
along the Mississippi River. We have not researched this so somebody may
want to correct or expand on this info. So Houston County is kind of in the
middle between these two regions. Remember that last summer Chris Wood
documented an adult Laughing Gull from this area of MN about this same time.
More research is to be done. Hopefully somebody will find this bird and be
able to digiscope it. We took a couple of very long shots today but
remember that we use film so don't expect the photos to be of much help. A
good digiscoper would have done well today. And a last note. We have very
little experience with Laughing Gull and very extensive experience with
Franklin's Gull. This whole thing started because this bird did not look
right for Franklin's Gull.
Dennis and Barbara Martin
Shorewood, MN
dbmar...@skypoint.com
----- Original Message -----
From: "Peder Svingen" <psvin...@d.umn.edu>
To: <MOU-NET@LISTS.UMN.EDU>
Sent: Saturday, August 07, 2010 6:54 PM
Subject: [mou-net] possible Laughing Gull, Houston County
Dennis Martin just called and asked me to post his sighting of a possible
first-cycle Laughing Gull in Houston County. The bird is sitting on an
island in the river (the same island where an avocet was seen last week)
about a quarter mile east of the wooden viewing platform along highway 26,
approximately 4 miles south of Brownsville. Due to the distance he has
been unable to evaluate bill size or shape, and he has not seen the bird
in flight. The bird is amongst a flock of several hundred Ring-billed
Gulls and looks smaller than all of the adjacent Ring-billeds. Dennis
stated that the folded primaries are solidly black and that its back is
clearly darker gray than the Ring-billeds, with brownish tertials.
Although the bird has extended its wings while preening, he has not been
able to see the ventral surface of its remiges and he has not seen its
tail pattern.
Dennis is keenly aware of how difficult it can be to distinguish
Franklin's and Laughing gulls and hopes that other birders are able to
refind this bird. In addition to Gulls of the Americas (Howell and Dunn)
and other books specifically addressing gull identification, birders may
wish to consult Kenn Kaufman's Advanced Birding field guide for further
guidance.
Thanks to Dennis for his timely report.
--
Peder H. Svingen
Duluth, MN
----
Join or Leave mou-net: http://lists.umn.edu/cgi-bin/wa?SUBED1=mou-net
Archives: http://lists.umn.edu/archives/mou-net.html
